📝Update readme

README.md

@@ -1,3 +1,43 @@
-# colsum
-Simple cli util for intersecting colors
+<div style="right:0; position: absolute; width: 100px; height: 150px; opacity: 80%">
+    <div style="position: absolute; width: 50px; height: 50px; background-color: blue; z-index: 2"></div>
+    <div style="top: 30px; left: 30px; position: absolute; width: 50px; height: 50px; background-color: aqua; z-index: 1"></div>
+    <div style="top: 30px; left: 30px; position: absolute; width: 50px; height: 50px; background-color: rgba(0,255,255,0.54); z-index: 3"></div>
+</div>
 
+# $ colsum
+
+Simple command line tool for overlaying colors
+
+```shell
+java -jar colsum.jar -b "aqua" -e "rgb(55, 12, 2, 0.4) + rgba(1, 50, 217, 0.3)"
+```
+
+<div style="font-size: 20px">
+Usage:<br>
+    <div style="margin-left: 25px">
+    — expression, -e -> Expression for computation (always required) { String }<br>
+    — background, -b [#FFF] -> background color { String }<br>
+    — help, -h -> Usage info<br>
+    </div>
+</div>
+
+# 🧑‍💻 For new contributors
+
+🚧 Under construction 🚧
+
+# 🔧 Internals
+
+A brief structural components overview
+
+## 🔍️ Parser
+
+🚧 Under construction 🚧
+
+## 🎨 Alpha composition formulas
+
+Сolors are superimposed like, for example, in the Mozilla Firefox browser. Formulas are presented below:
+
+```
+result alpha = background alpha * (1 - new alpha) + new alpha
+result color[R,G,B] = background alpha * (1 - new alpha) * background color + new color * new alpha
+```